Colon cancer survival is associated with increasing number of lymph nodes analyzed: a secondary survey of intergroup trial INT-0089.

PURPOSE: To determine the relationship, in patients with adenocarcinoma of the colon, between survival and the number of lymph nodes analyzed from surgical specimens. PATIENTS AND METHODS: Intergroup Trial INT-0089 is a mature trial of adjuvant chemotherapy for high-risk patients with stage II and stage III colon cancer. We performed a secondary analysis of this group with overall survival (OS) as the main end point. Cause-specific survival (CSS) and disease-free survival were secondary end points. Rates for these outcome measures were estimated using Kaplan-Meier methodology. Log-rank test was used to compare overall curves, and Cox proportional hazards regression was used to multivariately assess predictors of outcome. RESULTS: The median number of lymph nodes removed at colectomy was 11 (range, one to 87). Of the 3411 assessable patients, 648 had no evidence of lymph node metastasis. Multivariate analyses were performed on the node-positive and node-negative groups separately to ascertain the effect of lymph node removal. Survival decreased with increasing number of lymph node involvement (P =.0001 for all three survival end points). After controlling for the number of nodes involved, survival increased as more nodes were analyzed (P =.0001 for all three end points). Even when no nodes were involved, OS and CSS improved as more lymph nodes were analyzed (P =.0005 and P =.007, respectively). CONCLUSION: The number of lymph nodes analyzed for staging colon cancers is, itself, a prognostic variable on outcome. The impact of this variable is such that it may be an important variable to include in evaluating future trials.

Local excision and chemoradiation for low rectal T1 and T2 cancers is an effective treatment.

Lesions located in the distal third of the rectum are usually treated with abdominoperineal resection or a low anterior resection with a coloanal anastomosis. However, in a select group of patients with favorable histology and a low probability of lymphatic spread, sphincter-sparing procedures will afford long-term disease-free survival and cure without the need for extensive, complicated surgery. We performed a 10-year retrospective review, including pathologic examination of specimens by a single pathologist, in an attempt to identify factors associated with a decreased disease-free survival. Thirty-five patients (median age, 71 years; range, 48-88) with low rectal carcinomas were treated with full-thickness disc excision (with or without chemoradiation), with curative intent. Median follow-up was 46 months (range, 8-120). There were 15 T1, 16 T2, and 4 T3 lesions. Tumors with poor histologic factors or greater than T1 received adjuvant radiation (with or without 5-fluorouracil). Four patients developed a local failure at a median of 21.5 months (range, 9-30) and were salvaged with abdominoperineal resection. The 5-year cancer-specific survival was 91 per cent. Negative margins approached statistical significance (P < 0.07) in influencing local control. We conclude that, when combined with chemoradiation for lesions deeper than submucosa or with adverse histologic factors, local resection of rectal cancer is an effective treatment in selected patients.